What is a PRP injection?

Platelet Rich Plasma (PRP) injection is when a Specialist doctor injects parts of your blood (autologous) into injured body structures to help facilitate your recovery.

Our blood has four main parts; red blood cells, white blood cells, platelets, and plasma (the blood’s liquid). Platelets are different to red and white blood cells as they aren’t cells but small fragments of cells; they are most well-known for helping our blood clot. Platelets also contain a lot of proteins called growth factors, and these growth factors help facilitate healing.

Platelet-rich plasma is simply plasma with a higher than usual concentration of platelets in it. The process of preparing a PRP injection is quite simple:

  1. Your doctor takes a small amount of blood, similar to a routine blood test
  2. The blood is spun in a centrifuge to separate the platelets from the other blood cells
  3. Your doctor injects the platelet-rich portion of the plasma under ultrasound guidance into the injury site.

Injecting with ultrasound guidance helps ensure that the PRP penetrates the area it needs to have the most benefit. Ultrasound guidance enables real-time, visual confirmation of where the needle is going, which improves the accuracy of targeting the injured tissue. US guidance reduces the risk of unnecessary trauma and damage to nearby structures when injecting PRP into a joint like your knee or ankle.

How does a PRP injection work?

Injecting PRP into injured tendons or joints is beneficial due to the hundreds of growth factors that platelets carry; these growth factors speed up the healing process.

When used to treat chronic tendinopathies, PRP is thought to promote the growth of new blood vessels, increasing blood and nutrient supply to the damaged area of the tendon. This increase in blood flow and nutrient supply helps the damaged tissue heal. These supplies help stimulate new tissue formation and remove debris from the tendon’s damaged tissue.

PRP is also thought to carry cytokines (small proteins), which are involved in the signalling pathways that happen during the healing stages of inflammation, help increase cell production and remodel the new tissue that has formed.

What can a PRP injection be used to help treat?

Specialists can use PRP to assist in the treatment of a variety of conditions; recent research supports its use in the following conditions:

  • Tendon Injuries in the foot and ankle:
    • Plantar Fasciitis (chronic)
    • Peroneal tendonitis or tendinopathy
    • Achilles Tendonitis
  • Osteoarthritis of the ankle or other smaller joints in the foot eg Subtalar joint

What are the benefits of a PRP injection?

For patients with mild to moderate knee arthritis, PRP injections have been shown to reduce knee pain and improve their functional ability.

Studies have established PRP injections to be safer for patients with plantar fasciitis than corticosteroid injections (associated with plantar fascia rupture). Patients who had a PRP injection for their plantar fasciitis associated heel pain report a significant reduction in their pain and improved functional ability.

PRP injections are a safer option than traditional corticosteroid injections, which have been associated with increased rates of tendon rupture as well as causing atrophy to tissues in the region of the injection. Corticosteroid injections into a joint have also been shown to speed up the progression of osteoarthritis!


Are there any risks?

  • Pain at the injection site
  • Infection (very low <1%)